The cost of taking images from unmanned air vehicles have been reduced than that from airplanes and helicopters. Moreover, unmanned air vehicles are capable to take images low in the air safely even in small places and approach a target to be imaged. Since they can provide high-quality still and moving images, unmanned air vehicles have been applied in many fields, for example, to check the maintenance of structures, check heights, and observe ground from a high altitude.
The method of taking images with an unmanned air vehicle, including measuring the distance between the airframe and an object to be imaged while the unmanned air vehicle is flying; determining the zoom factor of the camera based on the result; and imaging the object is proposed (for example, refer to Patent Document 1). According to this method, the camera installed in an unmanned air vehicle can accurately capture the image of an object to be imaged, sufficiently enlarge the image within the frame of the camera, and record the image as high-definition image data. Therefore, the method can be beneficially and effectively used to check the surface of high structures and disaster sites to considerably reduce the cost required for the checks, compared with past methods.